The columnar curved tempered glass used in reality comprises two kinds, one is the equal arc columnar curved tempered glass as shown in FIG. 1, namely, the columnar curved tempered glass with cross section of circular arc; and the other one is the unequal arc columnar curved tempered glass as shown in FIGS. 2 (a, b, c and d), namely, the columnar curved tempered glass with cross section curve comprising a plurality of arc segments having different curvatures and/or straight segments.
A roller type bending device is usually used for manufacturing the equal arc columnar curved tempered glass. Such bending device comprises a roller type bending mechanism and a chiller cooling mechanism, and the rollers in the rollers bending mechanism are positioned between the upper and lower chillers in the chiller cooling mechanism. The roller type bending mechanism is divided into two kinds according to the operating mode, one is shown in FIG. 3 and FIG. 4, namely, the arrangement of each supporting roller in the rollers supporting high temperature flat glass is changed from planar arrangement in space into curved arrangement corresponding to the shape of the glass to be formed, so as to enable the glass to undergo bending deformation. Such bending mechanism is called as the first mechanism below. FIG. 3 is a schematic diagram showing the bending mechanism before deformation; FIG. 4 is a schematic diagram showing the bending mechanism after deformation. In the figures, 1 represents for a supporting roller; 2 represents for a glass plate and 3 represents for chillers. The other one is shown in FIG. 5, FIG. 6 and FIG. 7. The axis of each supporting roller in the rollers supporting the high temperature flat glass bends itself so as to enable the supported glass to undergo bending deformation. Such bending mechanism is called as the second mechanism below. FIG. 5 is a side view showing the bending mechanism before deformation; FIG. 6 is an end face view showing the bending mechanism before deformation; FIG. 7 is a schematic diagram showing the bending mechanism after deformation. The supporting roller with flexional axis in the figures can be constituted by a soft supporting roller, or constituted by combining a plurality of spaced rollers through a connecting device (not shown in the figures).
In a manufacturing process, firstly, the flat glass is fed into a heating furnace and heated, and then the heated high temperature flat glass 2 is fed into the bending device for bending and tempering. After the high temperature flat glass is fed to the rollers of the bending mechanism in the bending device, the high temperature flat glass undergoes bending and then tempering through a cooling mechanism. In the cooling tempering process, in order to ensure that the upper and lower surfaces of the glass and each position of the same surface have the same tempering effect as much as possible, the chillers in the tempering mechanism are arranged according to the corresponding shape of the curved glass subjected to bending to ensure uniform distance between each chiller and the glass surface, simultaneously, the supporting roller or the supporting unit needs to be continually rotated back and forth to swing the glass, thereby avoiding the influence of the supporting roller or the supporting unit on the tempering on the lower surface of the glass. Finally, for the first bending mechanism after the glass plate is tempered, the finished product of the curved glass is output by the rollers after each supporting roller is reset to be horizontally positioned; and for the second bending mechanism, the finished product of the curved glass is output by the rollers directly.
For the first bending mechanism, the curved glass subjected to bending swings perpendicular to the axis of the supporting roller in the tempering process, the swinging curved glass always keeps mutually parallel to the supporting roller and the chiller arrays positioned above and under the supporting roller when the equal arc curved glass is processed; and the swinging curved glass is not parallel to the rollers and the chiller array when the unequal arc curved glass is processed, so that the precise bending of the curved glass is affected, as well as the swinging curved glass will collide with the chiller thereabove and is crushed, and only the second bending mechanism can be used for processing the unequal arc columnar curved tempered glass.
When the unequal arc columnar curved tempered glass is processed by using the second bending mechanism, though the problem that the curved glass collides with the chiller array thereabove while it undergoes tempering and swinging is avoided, obvious wavy deformation always exists at both sides of the formed curved glass adjacent to each supporting roller due to the fact that the high temperature flat glass is driven by a plurality of the supporting rollers arranged between the rollers at intervals to complete the deformation of the glass, so it is difficult to meet high quality requirement of the curved glass article. Certainly, wavy deformation also exists at both sides of the curved glass adjacent to each supporting roller while the equal arc curved tempered glass is processed by the second bending mechanism.
Moreover, as the front and back ends of the high temperature flat glass depart from the glass heating furnace at different time and have different outside cooling time, temperature gradient exists from the front end to the back end of the high temperature flat glass while the high temperature flat glass has entered the bending mechanism. The front end of the glass has lower temperature than that of the back end, and the larger the size of the glass in the forward and backward direction, the higher the temperature gradient in the forward and backward direction, whereas the temperature before the glass is bent directly relates to the result of bending. Compared with the front end with low temperature, the back end with high temperature is easier to bend, so that the curved tempered glass subjected to bending has a bit smaller curvature near the front end than that near the back end, and the quality of the curved tempered glass is also affected.